1. Field
The present invention relates to industrial vehicles and more particularly to extensions for the forks of fork lift trucks of the type shown in the parent application.
2. Description of the Prior Art
The known prior art is cited in the parent application, and is as follows:
McCracken U.S. Pat. No. 3,050,206, for Load Handling Systems, shows an I beam for extending a load engaging member thru a swivel joint.
Costello U.S. Pat. No. 3,258,145, for Stepped Pallet Forks, discloses a horizontal extension member which is bolted to the forks and fits over the forks to impart steps thereto.
Stevenson U.S. Pat. No. 2,068,825, for Industrial Truck, shows a C-shaped lift member supported from an I-beam that rides on the truck lift members.
Lynch U.S. Pat. No. 3,930,585, discloses a lift fork extension using a slightly different swivel connection than those shown in the McCracken and Stevenson patents.
Miles, et al. U.S. Pat. No. 3,850,322, for Side Loading Device for Fork Lift Trucks, discloses a swivel platform attachment for lift trucks.
Russian Inventor's Certificate No. 267472 discloses a fork lift truck with swivel hook attachment at its forward end.
Russian Inventor's Certificate No. 540876, discloses a lift truck attachment for lifting differently shaped loads.
Of the above prior art, only Stevenson and Miles disclose the use of an intermediary extension structure for going from the forks of a fork lift truck to extended surrogate forks, but neither of these patents anticipate the use of a relatively long, single channel member with a much shorter lift or guard strap at each end as the entire extending and interconnecting member between the lift truck forks and the corresponding surrogate forks. None of the other prior art references disclose this structure, and most disclose and require separate locking means (bolts, etc.) for maintaining the extension member is the desired physical relationship between the forks of the lift truck and the forks at the load.